Targeting is based on the deep present-day knowledge about the molecular mechanisms of cell functioning. The use of targeted drugs for medical treatment is called targeted therapy. Targeted drugs are a new class of drugs that have a selective action on molecular targets in diseased cells, for example, tumour cells or vascular lesions. In oncology, drug targets include receptors for epidermal and vascular growth factor (angiogenic receptor); proteins involved in mitogenic signal transduction from receptor molecules; molecules that control the process of programmed cell death. In other words, the targets for such drugs (in cancer treatment) are the organism’s own proteins, involved in carcinogenesis and promoting tumour progression and metastasis. A new promising targeted gene therapy of cancer is aimed at silencing genes responsible for cancer cell growth by means of RNA interference (inhibition of gene expression at the translation level by small interfering RNA). In general, the molecular targets for targeted therapy are the selective markers - biocomponents at the lesion site.